WO2003096053A2 - Certification, identification et poursuite automatiques d'objets distants en mouvement relatif - Google Patents

Certification, identification et poursuite automatiques d'objets distants en mouvement relatif Download PDF

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Publication number
WO2003096053A2
WO2003096053A2 PCT/IL2003/000378 IL0300378W WO03096053A2 WO 2003096053 A2 WO2003096053 A2 WO 2003096053A2 IL 0300378 W IL0300378 W IL 0300378W WO 03096053 A2 WO03096053 A2 WO 03096053A2
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WIPO (PCT)
Prior art keywords
tag
radiation
information
coded information
imaging
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PCT/IL2003/000378
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English (en)
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WO2003096053A3 (fr
Inventor
Amit Stekel
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Amit Stekel
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Application filed by Amit Stekel filed Critical Amit Stekel
Priority to US10/513,886 priority Critical patent/US20060000911A1/en
Priority to AU2003230169A priority patent/AU2003230169A1/en
Publication of WO2003096053A2 publication Critical patent/WO2003096053A2/fr
Publication of WO2003096053A3 publication Critical patent/WO2003096053A3/fr

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/04—Detecting movement of traffic to be counted or controlled using optical or ultrasonic detectors
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/017—Detecting movement of traffic to be counted or controlled identifying vehicles

Definitions

  • the present invention relates to the field of remote tracking systems, especially for use in determining the identity and motion of a moving remote object by means of an optical identity tag carried thereon.
  • optical systems such as license plate recognition systems
  • license plate recognition systems are sensitive to lighting variations, cannot handle massive flows and necessitate the assistance of a human operator to analyze cumbersome images of license plates that the processing software cannot recognize.
  • Other optical systems based on barcode reading, generally have limited contrast and spatial resolution.
  • Commonly used barcode systems based on laser scanning are generally limited to static or quasi-static situations; in dynamic situations, where the barcode is in motion, the signals tend to smear and the resolution is degraded.
  • Normal barcode systems are also limited to close proximity between the scanner and the barcode; at large distances, the spatial resolution is again degraded because of insufficient sampling.
  • US Patent No 6,017,125 to Vann discloses the use of a bar coded retroreflective target to measure six degrees of target position and the use of a bar coded retroreflector to provide information about the target. These designs use the object motion to scan a barcode pattern that is combined with retroreflective optics, either a cube retro reflector or a ball lens retro reflector. In addition, the designs disclosed in this patent are bulky, are probably costly to manufacture, and thus may not be suited for mass usage.
  • the entire field of view of the object or objects being scanned or tracked are described as being focused onto the detector, which is alternatively described as being either a position sensitive detector, or an array of photodiode elements or a camera.
  • the decoding of the information is determined by signal processing of the time-varying digital signals obtained from these detectors.
  • radio frequency waves There are yet other types of system that use radio frequency waves, namely radar devices. These systems installed in urban vicinities are restricted by radiation regulations and necessitate an authority license for operation. In a lot of cases, this limits their maximum power to relatively low levels. This in turn, narrows the communication zone and worsens the electromagnetic interference noise situation, resulting in a poor signal-to-noise ratio. Furthermore, radio frequency based systems are susceptible to inter- modulation or cross talk between tags that may be addressed at the same moment in time. Finally, in applications where the position and speed are desired in addition to the vehicle identity, radar devices tend to confuse between neighboring vehicles. SUMMARY OF THE INVENTION
  • the present invention seeks to provide a method and apparatus for automatic certification, identification and tracking of remote objects in relative motion to a reading system, and in particular a system comprised of a novel tag affixed to an object and novel apparatus and techniques for automatically reading the tag information, its relative velocity, angle and position.
  • the relative motion between the reader and the tag may occur in either one of three situations: (i) a stationary reader and moving tag; ( ⁇ ) a stationary tag and moving reader, as in a scanning detector; and (iii) a situation with both tag and reader moving in relative motion to each other.
  • the system has particular application to the problem of vehicle identification, as well as the measurement of their speed and position simultaneously.
  • Another application of the system of the present invention is for the provision of automatic and maintenance-free road signposts, where signpost data could be read from a moving vehicle and from a remote distance.
  • Yet another application is the scanning of inventory in places such as warehouses, museums etc., where readers are installed on entrances, or may be conveyed on rail arrangements so as to scan each tagged item swiftly.
  • the present invention attempts to overcome the difficulties associated with prior art systems, as outlined in the Background section, by providing a novel optically readable system and method for the remote identification of objects in relative motion, such as vehicles, in addition to speed and position determination.
  • the system preferably comprises a separate reader unit and an optical tag unit, preferably on the moving object.
  • the system generally comprises a light source that is preferably monochromatic, an imaging device having its optical axis and field of view exactly bore sighted with the light source, and a retroreflective tag preferably attached to the moving object.
  • the system differs from the prior art systems described above, in that the field of view of the reader unit is imaged by the detection means, preferably a video imager, such that a complete image of the entire field of view is captured at every moment.
  • This image which can contain retro-reflected information from multiple tags, can be processed by means of standard image processing techniques, and temporally changing information about each tag extracted separately on each pixel, without any confusion or mixing between different tags.
  • Yet another object of the present invention is to provide for a system and a tag that can be read at high relative velocities.
  • the optical tag uses optical elements to image the information plane of the tag, preferably a barcode, back to the reader unit aperture plane, and uses the tag's motion to scan the tag's information plane, such that the spatial information contained in this plane is transformed to a temporal scanning signal that can be acquired by the reader's video imager.
  • the present invention provides a maintenance free and low-cost optical tag that use retroreflective means to reflect and modulate the reader's light, back to the reader's imaging device, without the need for an internal source of energy.
  • the present invention provides a method and a system that can automatically detect and identify a remote tag in relative motion to the scanner, utilizing the tag's unique spatio-temporal features as a trigger for the reader activity.
  • the present invention provides a system that can be used in severe lighting conditions, utilizing a retroreflective tag that, together with an active illumination with monochromatic hght and a suitable filtered imaging device, can suppress spurious light sources and enhance the tag reflective Ught.
  • the present invention provides a system that can be read from relatively large distances, utilizing a retroreflective tag and a bore sight arrangement of the reader's Ught source and the reader's imaging device.
  • the present invention allows for simultaneous identification and measurement of speed and position of multiple moving objects or vehicles.
  • the system allows for multiple reading of neighboring tags with negUgible cross talk between them such that even high flows of moving objects or high traffic flows can be read successfully without degradation in system performance.
  • the present invention provides means to handle dirt and smudge in the optical path, by locating the tag near the front windshield of a vehicle, so that if it is covered, the driving visibiUty will also be degraded and steps taken to rectify the situation.
  • the present invention provides for covert operation using light in the infrared region.
  • the tag can be detected from the reader alone and no light is scattered to another directions.
  • the present invention provides for automatic and remote certification of tagged objects using special optical means to prevent counterfeiting.
  • the present invention provides for the production of a cost effective, thin and lightweight tag that can be affixed easily to various objects.
  • the present invention provides for cost effective ways for the production of the proposed tag.
  • the present invention provides for scanning schemes that reduce the geometrical limitations of the tag reading. Other objects and advantages of this invention will become apparent as the description proceeds.
  • Fig. 1 An illustration of a first embodiment of the moving tag reader apparatus, i.e. an MTR, in accordance with a preferred embodiment of the present invention
  • FIG. 2A An illustration of an optional embodiment of the moving tag reader apparatus, i.e. an MTR, using fiber optics located at the center of the lens, in accordance with another preferred embodiment of the present invention
  • Fig. 2B An iUustration of an optional embodiment of the moving tag reader apparatus, i.e. an MTR, using fiber optics on the lens optical axis, in accordance with another preferred embodiment of the present invention
  • Fig. 2C A side view of an optional embodiment of the moving tag reader apparatus, i.e. an MTR, using Ught sources distributed around the camera lens, in accordance with another preferred embodiment of the present invention
  • Fig. 2D An upper view of an optional embodiment of the moving tag reader apparatus, i.e. an MTR
  • Fig. 3A-C A schematic iUustration relating to the temporal aspects of the invention, showing the various phases of operation of the invention, in accordance with another preferred embodiment of the present invention
  • Fig. 4A, B iUustrations of an optional embodiment of the reader and tag where the moving tag is read by a multi directional scanning system, in accordance with another preferred embodiment of the present invention
  • Fig. 5 illustrations of optional embodiments of the reader and tag where the moving tag is read from an arbitrary direction using a Circular Barcode pattern, in accordance with another preferred embodiment of the present invention
  • Fig. 6 iUustrations of an optional embodiment of the tag, where the focusing optics is constructed of a lenslet array such as a Diffractive Optical Element (DOE) Array, in accordance with another preferred embodiment of the present invention;
  • DOE Diffractive Optical Element
  • Fig. 7 A detailed illustration of an optional embodiment of the optical tag, where the tag information plane is curved along a sphere, in accordance with another preferred embodiment of the present invention
  • Fig. 8A, B iUustrations of an optional embodiment of the tag, where the tag retro-reflection is enhanced, in accordance with another preferred embodiment of the present invention
  • Fig. 9 Ulustrations of an optional embodiment of the tag, where the tag is constructed of a single surface DOE, in accordance with another preferred embodiment of the present invention.
  • Fig. 10 An overall illustration of a preferred embodiment of the invention being used to identify moving objects, in accordance with another preferred embodiment of the present invention
  • Fig. 11 A A schematic iUustration of the scene viewed by the reader's imager, showing the tagged objects or vehicles in motion, in accordance with another preferred embodiment of the present invention
  • Fig. 11B A schematic Ulustration relating to the filtered image acquisitioned by the reader's video imager showing the tags' retroreflective responses, in accordance with another preferred embodiment of the present invention
  • Fig. 12 A schematic illustration depicting the process of accumulating the tag data in the reader, in accordance with another preferred embodiment of the present invention.
  • Fig. 13 A block diagram depicting code and data flow of the signal processing process, in accordance with another preferred embodiment of the present invention.
  • Fig. 1 shows a schematic layout of the system of the present invention comprising a moving tag reader, (MTR), 10, for automatic identification, speed assessment and position determination of moving tags, in accordance with a preferred embodiment of the present invention.
  • the MTR 10 optionally comprises a camera 11 having a lens 12 and an imager 13, a Ught source 14 and a beam spUtter 17.
  • a controUer 52 controls the light source 14 and camera 11 and also preferably comprises an image processor for processing images acquired by the camera of the entire field of view of the MTR.
  • Ught source 14 and camera 11 optionally have coincident optical axes 20 by means of a bore sight arrangement using beam spUtter 17, and optionally have the same field of view 21 by suitable choice of the numerical aperture of the lens 12 and the cone of Ught 21 A emitted by the Ught source.
  • the Ught source can preferably be either a regular lamp source emitting a diverging beam to cover the desired field of view, or a laser source emitting a coherent beam, together with a negative lens for providing a sufficiently diverging beam if the laser is too colUmated.
  • a tag 30, instaUed on a moving object, such as a vehicle, is comprised of a lens 31 and an information plane, 32.
  • the tag 30 and the MTR 10 are optionaUy arranged to have the same depth of field and the same field of view by appropriate choice of the parameters of lens 12 and lens 31 and the distances of their imaging planes 13 and 32 from their respective lenses. This assures that the MTR and tag are optimally optically coordinated to work together, having both optimal visibility and resolution.
  • a light ray, 22 A, emitted from light source 14 is reflected from the beam splitter 17 to the direction of the tag as light ray 22.
  • Any light ray in the cone 23, including light ray 22, is eventually focused to the same focus point 32A in the tag information plane 32.
  • part of the light from the focal point 32 A is reflected through the light cone 33 back to the entrance pupil of the tag lens 31, focused back to the direction of the MTR 10, transmitted through the beam splitter 17, enters the camera lens 12 entrance pupil and is imaged to the point 13 A on the imaging plane 13 of the camera 11.
  • This tag configuration is called a "retro reflector" because it retro reflects any beam in its entrance pupil back to its original direction.
  • the tag configuration has the useful feature of focusing the beam back to its point of origin, which in the layout described in Fig. 1 is co-aligned with the camera entrance pupil.
  • the information plane 32 is optionally comprised of a retro reflective sheet. In this way the tag reflecting efficiency is enhanced because most of the light rays incident on the focus point 32A is reflected back to the tag lens 31 entrance pupil.
  • Fig. 1 there is shown in Fig. 1 an optional chromatic filter 15 and two aligned polarizers 16. These optional means are useful for enhancing tag response and rejecting responses from spurious sources.
  • the color filter 15 is matched to a monochromatic light source 14 and the two linear polarizers are aligned so that light coming out of the light source 14 can reach the camera 11 with minimal interference and light coming from other light sources, such as sunlight reflections or vehicle lights, is reduced substantially.
  • Fig. 2 A shows another preferred embodiment of the MTR of the present invention, in which the light source, 14, is collimated by means of a single-fiber collimator 19 into an optical fiber, 19A.
  • the end of the fiber is optionally inserted into a hole, 12 A, in the imaging lens, 12.
  • the fiber end can be disposed behind the lens center, at 19B, such that the combined numerical aperture of the paraxial portion of the lens and fiber is essentially the same as that of the full aperture of the lens.
  • the lens hole 12A is then unnecessary.
  • Fig. 2A typical of high numerical aperture applications, Fig.
  • 2B shows yet another preferred embodiment, in which the end of the fiber is optionally fixed in front of the lens, 12, co aUgned to its optical axis, 20.
  • the paraUax between the Ught coming out of the fiber, 22A, and the retro reflected Ught coUected by the imaging lens, 22B, is negUgible.
  • Figs. 2C and 2D show a side view and an upper view, respectively, of another preferred embodiment of the MTR of the present invention, in which a number of light sources are distributed around the imaging lens, 12. Such an embodiment may be realized using a ring of LED's placed around the lens.
  • Fig. 2C shows a side view of a particular distribution, where two Ught sources, 14A and 14B, are located on two sides of the imaging lens, 12, in a perpendicular direction to the scanning direction.
  • the beams 25 A and 25B, coming of the Ught sources 14A and 14B respectively, are focused on 32A and 32B, respectively, on the information plane, 32 of the tag, 30.
  • the two focuses have point spread functions, 34A and 34B, accordingly and thus a combined response 34C that in turn is retro reflected in a direction surrounding the direction 22, back to the MTR entrance pupU.
  • Fig. 2D shows an upper view of this embodiment, where the two point spread functions are located on the same vertical location along the scanning direction.
  • This embodiment of the MTR is typical of applications where the numerical aperture is especiaUy high, and enables the paraUax between the light coming out ring of LED's and the retro reflected Ught coUected by the imaging lens, 12, to be negUgible.
  • the information plane 32 optionaUy comprises a barcode pattern having its chief axes, i.e. the scan axes, co aligned with the direction of the object motion.
  • Figs. 3A-C are a series of sequential schematic Ulustrations, showing the motion of a tagged object 40 across the field of view of the reader unit 10, in accordance with another preferred embodiment of the present invention.
  • the drawings iUustrate graphicaUy the way in which the spatiaUy moving information on the tag 30 is transformed into meaningful and simply read temporal information by means of the optics of both the tag unit 30 and the reader unit 10.
  • Fig. 3A-C are a series of sequential schematic Ulustrations, showing the motion of a tagged object 40 across the field of view of the reader unit 10, in accordance with another preferred embodiment of the present invention.
  • the drawings iUustrate graphicaUy the way in which the spatiaUy moving information on the tag 30 is transformed into meaningful and simply read temporal information by means of the optics of both the tag unit 30 and the reader unit 10.
  • the tagged object 40 is shown entering - li the field of view of the reader unit 10, at which point, the mutual geometries of the imaging optics of reader and tag units are such that the first bar of information 32A on the tag information plane 32 retro -reflects the incident illuminating beam and is imaged by the read unit on the camera image plane 13 as point 13 A.
  • the mutual fields of view of the reader and tagged units change such that retro-reflected rays from different bars of the tag are sequentiaUy imaged onto the camera image plane.
  • bar 32 B is imaged onto point 13B on the camera imaging plane
  • Fig. 3C the bar at 32C is imaged onto point 13C by the camera.
  • the entire bar code information is sequentiaUy imaged onto the camera image plane 13 such that the system controller acquires a temporally changing image of the tag information.
  • a collimated laser beam, swept across the bar-code is used in order to convert the spatial information on the bar code into temporally changing information for serial processing.
  • the system of the present invention differs from this prior art in that the optics incorporated on the tag enlarge each bit of the information plane so that it is fuUy resolved by the reader even at substantially large distances, such that the tag may be kept relatively small.
  • the system of the present invention differs from such prior art in that the effective scanning motion of the interrogating iUuminating beam across the bar-code, and its retro-reflected information-bearing beam, are generated by means of the relative motion of the limited fields of view of both reader and tagged units resulting from the use of the pre-specified optical imaging systems on both of these units.
  • the effective scanning motion of the interrogating iUuminating beam across the bar-code, and its retro-reflected information-bearing beam are generated by means of the relative motion of the limited fields of view of both reader and tagged units resulting from the use of the pre-specified optical imaging systems on both of these units.
  • Fig. 4A and B iUustrate an optional preferred embodiment of the reader and tag where the moving tag is read by a multi-directional scanning system, in accordance with an embodiment of the present invention.
  • the tag information plane is optionaUy constructed of several barcode segments.
  • Fig. 4A represent the case of two separate barcodes located in the tag's information plane. The barcodes are located in different locations along the Y-axis, perpendicular to the reading direction, X.
  • the tag can comprise two identical barcodes to provide increased reliability by redundancy.
  • Fig 4B shows two readers positioned in the appropriate angles, each of them reading the corresponding barcode segment.
  • Fig 5 illustrates an optional embodiment of the reader and tag combination, where the moving tag is read from an arbitrary direction using a Circular Barcode pattern, in accordance with another preferred embodiment of the present invention; this optional configuration is suggested for situations where there is no guarantee that the barcode segment in the tag's information plane is aligned to the reading direction but it certain that the tag path is crossing through the reader's optical axis. Thus, independently of whether the tag is read along direction 35A or 35B, for instance, the information thereon is correctly imaged and decoded.
  • the tag angle versus the reader optical axis direction may be recovered using the tag's reflected color.
  • This feature is made possible by using a multicolored plane of information, 32, where each point on the plane features a unique color corresponding to a distinct angle of view. Having in advance knowledge of the information plane color scheme enables the retrieving of the tag angle versus the reader's optical axis direction, by identifying the tag retro reflection color.
  • the reader may optionally be a multi spectral reader such as color video camera.
  • the tag's position is related to its image in the reader's imaging plane and the velocity of the tag can be recovered by temporal derivation of the tag's position vector. Using features such as angle, position and velocity the tag can be traced or even may be used as a reference for automatic navigation.
  • Fig. 6A shows another preferred embodiment of the tag, where the focusing optics is constructed of a Lenslet Array 31, in accordance with an embodiment of the present invention; this embodiment is useful whenever a lightweight and thin tag is desired.
  • the number of array cells used is dependent on the reading distance of the application, the light power needed and the reading resolution available.
  • the lenslet array 31 can be created of a Diffractive Optical Element (DOE) Array. DOE's are particularly adaptable for monochromatic Ulumination and imaging systems and can incorporate corrections for spherical aberrations.
  • DOE Diffractive Optical Element
  • the information plane of the tag array is constructed of a periodical pattern having the same period as the optical array.
  • the fitting of the periodical pattern can be done in numerous ways. One way is by printing a marker in a known location within the pattern and inserting the pattern into the optical array using an automated bench, having an optical feedback mechanism.
  • the fitted pattern in the optical array can be left unaligned.
  • the optical marker can be identified with the reader in real time, thus the read barcode pattern can be prearranged in a cyclic manner.
  • the spatial information stored within the tag can be alternatively stored in a multi layered interference filter, and assigning to each angle of interrogating beam incidence, a different reflectance. This ensures that while the tag is in motion, the interrogating beam scans different angles of incidence and thus responds to the information coded within the tag.
  • Fig. 7 shows a detailed iUustration of the optical tag configuration where the information plane 32 is curved along a sphere at the focal distance from the tag lens 31. Using this configuration, the focus point 32A, of the chief ray 33, is adequately focused for each direction the tag is interrogated.
  • DOE DOE
  • the present invention provides for a system that can be used in severe Ughting conditions, utUizing a retroreflective tag that, together with active illumination with monochromatic Ught and a suitable filtered imaging device, can suppress spurious Ught sources and enhance the tag reflective light.
  • Fig. 8A and B shows a further preferred configuration of the retro-reflective tag.
  • Fig. 8A shows the tag's backplane, made of multiple micro -mirrors, 36, each is directed towards the tag lens's center, 37.
  • the beam shown in Fig. 8B, spanning from ray 38A to ray 39A, is focused at the tag back plane at point 36 A, is mirror-imaged and reflected back onto itself, thus being retro-reflected.
  • Ray 38A is reflected to ray 38B that is on the same path but opposite to ray 39 A.
  • Ray 39A in its turn, is reflected back to the same path as ray 38A but to the opposite direction.
  • Fig. 9 shows a single surface tag that is constructed of a single surface DOE, 44, to encode the angular reflection spectrum of a barcode, 47.
  • the DOE is preferably constructed of a lens and a combination of diffraction gratings, each one have a pre specified cycle frequency and thus having a consequent diffraction direction. Together, the lines create the characteristically barcode lines.
  • the lens is designed to focus the reader's radiation back to its origin and even more importantly, bring closer the Fraunhofer diff action pattern, located typically at large distances, so it can be observed by the reader, as known in the art (Introduction to Fourier Optics/ Joseph W. Goodman, p. 61, 83-86).
  • the reader iUuminates the tag from direction 42.
  • the main specular reflection, 45 comes from the opposite side of the DOE optical axis and the diffracted rays, 46, construct the angular spectrum, 47, of the DOE, spanning both sides of the main reflection, 45.
  • the reader located in direction 42, because of its relative motion with respect to the DOE, temporaUy samples the diffraction spectrum across the whole of the diffracted Ught angle.
  • the location of the image of each line of the tag's information plane is proportional to its location within the information plane and the tag's focus length, and is not affected by the velocity of the tag or its acceleration.
  • the image acquisitioned by the reader's camera is robust to change in tag velocities even at high relative velocities, or in the presence of tag accelerations.
  • the Ught integration of the camera's detector is affected by the tag's velocity. At high tag velocities, the light response is smaUer. This problem is easily solved using tag reflective enhancement properties and further selecting high-powered Ught source.
  • the present invention provides means to handle dirt and smudge in the optical path, by locating the tag near the front windshield so that if it is covered, this is a sign that the driving visibiUty is also degraded and steps wiU be taken to rectify the situation.
  • more tags can be affixed to the front windshield such that aU of them are read simultaneously in order to gain redundancy.
  • the reader Ught source can be made adaptive to the weather conditions since drivers do not see infrared light and there is no radiation hazard using this band.
  • vehicles usuaUy reduce their speed thus compensating for the poor visibiUty.
  • the suppression of spurious light sources is very high relative to the reflectivity of the tag. This is made possible by the high reflective efficiency of the tags and the monochromatic and polarization filtering of the reader.
  • the present invention provides for covert operation using Ught in the infrared region.
  • the present invention provides for automatic and remote certification of tagged objects using special optical means to prevent counterfeiting, as is known in the art.
  • the present invention provides for a system that can be read from relatively large distances, utilizing a retroreflective tag and bore sight arrangement of the reader's Ught source and the reader's imaging device.
  • the tag reflective efficiency can be improved by selecting larger tag aperture diameters.
  • Fig.10 shows an overall illustration of the preferred embodiment of the invention being used to identify moving objects or vehicles, 40, in accordance with an embodiment of the present invention.
  • the reader, 10, may be instaUed on top or on the side of the path of the object, 40..
  • the object may be a vehicle.
  • the tag, 30, positioned on the vehicle, is read by the reader, 10, and then further transferred to a controUer, 52, for further processing.
  • the controller, 52 may comprise a host computer and a video frame grabber, 50.
  • Fig. 11A shows a schematic iUustration of the scene viewed by the reader imager, showing the tagged objects or vehicles in motion, 40, in accordance with another preferred embodiment of the present invention.
  • the objects, 40 carry tags, 30, and move along the read zone, 41, of the reader.
  • Fig.1 IB shows a schematic iUustration relating to the filtered image acquisitioned by the reader's video imager showing the tag retroreflective responses, 121, in accordance with another preferred embodiment of the present invention.
  • Fig. 12 shows a schematic iUustration depicting the process of accumulating the tag data in the reader, in accordance with another preferred embodiment of the present invention.
  • the tag's response, 121 is identified and then accumulated to form the accumulated image of the barcode, 124.
  • Fig. 13 shows a block diagram depicting code and data flow of the signal processing process, in accordance with another preferred embodiment of the present invention.
  • the processing of this invention is digital processing.
  • Grabbing an image by the camera such as those of the apparatus of this invention, generates a sample image on the focal plane, which sampled image is preferably, but not a two-dimensional array of pixels, wherein to each pixel is associated a value that represents the radiation intensity value of the corresponding point of the image.
  • the two-dimensional array of pixels therefore, is represented by a matrix consisting of an array of radiation intensity values.
  • Each sampled image is provided with a corresponding coordinates system, the origin of which is preferably located at the center of the sampled image.
  • Pixel Segment is a group of connected pixels sharing common features or a group of features.
  • Segment labeling is the process of assigning each pixel in the image with a value of the segment to which the pixel belongs.
  • Segment feature extraction procedure is the process that assigns to each segment its features, such as segment area or number of pixels, segment mass, which is the sum of the pixel's gray levels, segment various moments, such as the moment of inertia, etc.
  • Segment classification procedure is the process of assigning a class or type to a segment according to the amount of resemblance of its features to the known features of the various classes.
  • TemporaUy accumulated barcode segment list is the Ust of aU barcode-classified segments from aU frames; each segment is stored with its features and its video frame origin.
  • Frame i, 52b is grabbed within the frame sequence 52a.
  • the various segments of pixels are segmented using spatio-temporal filtering 52c as weU as morphological filtering to form the segmented image i, 52d, as is known in the art.
  • the various segments are then labeled, 52e, to form the segment list i, 52f.
  • a feature extraction procedure, 52g is than appUed to form the featured segmented list i, 52h, as is known in the art.
  • a segment classification procedure is than applied to distinguish the signal segments from the spurious noise segments to form the temporally accumulated barcode segment list52j, as is known in the art.
  • the barcode segments, 52j, are then merged, 52k, using the segments features, such as their locations etc. to form the merged barcode strings, 521.
  • Each barcode string is than decoded, 52m, to form the decoded tag information, 52n.
  • the information content of the tag is limited by the spot size of the optical system of the tag and the size of the information plane.
  • the actual capacity in bits, or the number of resolvable barcode lines is the ratio of the information plane length to the lens focus spot width.
  • the unique spatio-temporal behavior of the tag is utilized to automaticaUy detect its presence within the field of view of the reader. As the moving tag enters the reader's field of view, it wiU be seen flickering and thus its detection and the initiation of decoding can be done automatically.
  • the sampling of the barcode signal is done in the reader camera.
  • spatio-temporal sampling is sought; both spatial and temporal samplings are needed for simultaneous tag reading without cross talk between their respective signals. There are some tradeoffs between the spatial and the temporal sampling of the signal according to the information merits needed.
  • the tag position can be sampled by the spatial sampling alone whUe the tag's information content may be sampled both spatiaUy and temporaUy.
  • the combined spatio-temporal sampling scheme resolves both the tag's information content and the position vector of the tag.
  • the position vector provides the tag location; its temporal derivative provides the tag's speed and its scalar multiplication with the reader's direction of viewing vector provides the tag's relative angle to the reader's viewing direction.
  • the simplest situation of tag reading is the case where there is no need to resolve its position and there is only one tag that may be present at a time. In this situation, temporal sampling alone is sufficient.
  • This sampling scheme results in relatively simple signal acquisition and processing where the reader's imaging plane is preferably comprised of a single detector, usuaUy a single photodiode.
  • the reader's imaging plane is preferably comprised of a single detector, usuaUy a single photodiode.
  • spatial sampling is needed as well.
  • the position determination is needed at relatively high resolution
  • the spatial resolution alone may resolve both the tag's information and position.
  • the number of pixels in the sampling matrix Umits the information content that can be resolved.
  • the sampling may be one dimensional, e.g. a linear array of pixels.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Image Input (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

Abstract

Cette invention se rapporte à un procédé et à un appareil servant à la certification, à l'identification et à la poursuite automatiques d'objets distants en mouvement relatif par rapport à un système de lecture, et utilisant à cet effet une nouvelle étiquette électronique fixée sur les objets et un nouvel appareil et de nouvelles techniques permettant la lecture automatique des informations de l'étiquette électronique, sa vitesse relative, son angle et sa position. Le lecteur d'étiquettes électronique comprend un système d'imagerie qui réalise un traitement en temps réel des images acquises. La mise en correspondance des paramètres optiques de l'optique d'imagerie au niveau du lecteur et l'optique de focalisation au niveau de l'étiquette assurent la fiabilité optique et la lisibilité des étiquettes jusqu'à des portées étendues. De nouveaux types de modèles d'étiquettes électroniques sont présentés.
PCT/IL2003/000378 2002-05-07 2003-05-09 Certification, identification et poursuite automatiques d'objets distants en mouvement relatif WO2003096053A2 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US10/513,886 US20060000911A1 (en) 2002-05-07 2003-05-09 Automatic certification, identification and tracking of remote objects in relative motion
AU2003230169A AU2003230169A1 (en) 2002-05-07 2003-05-09 Automatic certification, identification and tracking of remote objects in relative motion

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37876802 2002-05-09
US60/378,768 2002-05-09

Publications (2)

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WO2003096053A2 true WO2003096053A2 (fr) 2003-11-20
WO2003096053A3 WO2003096053A3 (fr) 2005-01-20

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7075438B2 (en) 2004-07-30 2006-07-11 Hewlett-Packard Development Company, L.P. Tagging systems
WO2009013739A1 (fr) * 2007-07-24 2009-01-29 Elbit Systems Ltd. Système et procédé pour une détermination de niveau de visibilité et un comptage de véhicule

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4123651A (en) * 1977-07-13 1978-10-31 United Technologies Corporation Apparatus and method for speckle tracking
US4203133A (en) * 1975-04-04 1980-05-13 Thomson-Brandt Optical player with half wave plate
US4462095A (en) * 1982-03-19 1984-07-24 Magnetic Peripherals Inc. Moving diffraction grating for an information track centering system for optical recording
US5052637A (en) * 1990-03-23 1991-10-01 Martin Marietta Corporation Electronically stabilized tracking system
US5096281A (en) * 1987-10-21 1992-03-17 Optical Profile, Inc. Optical transform system
US5973309A (en) * 1997-08-27 1999-10-26 Trw Inc. Target-tracking laser designation

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4203133A (en) * 1975-04-04 1980-05-13 Thomson-Brandt Optical player with half wave plate
US4123651A (en) * 1977-07-13 1978-10-31 United Technologies Corporation Apparatus and method for speckle tracking
US4462095A (en) * 1982-03-19 1984-07-24 Magnetic Peripherals Inc. Moving diffraction grating for an information track centering system for optical recording
US5096281A (en) * 1987-10-21 1992-03-17 Optical Profile, Inc. Optical transform system
US5052637A (en) * 1990-03-23 1991-10-01 Martin Marietta Corporation Electronically stabilized tracking system
US5973309A (en) * 1997-08-27 1999-10-26 Trw Inc. Target-tracking laser designation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7075438B2 (en) 2004-07-30 2006-07-11 Hewlett-Packard Development Company, L.P. Tagging systems
WO2009013739A1 (fr) * 2007-07-24 2009-01-29 Elbit Systems Ltd. Système et procédé pour une détermination de niveau de visibilité et un comptage de véhicule

Also Published As

Publication number Publication date
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